Laryngoscopes are well known in the art, as exemplified by Upsher U.S. Pat. Nos. 4,437,458; 4,406,280; and 4,517,964, all of which are incorporated herein by reference. Each of these latter patents discloses what may be referred to as a fiber optic type of laryngoscope as distinguished from the more conventional laryngoscope which does not utilize fiber optics. The conventional laryngoscope includes a handle and a blade disengagably connectable to the handle. A conventional laryngoscope blade carries its own light source which is energized by batteries contained within the handle when the blade is connected to the latter. In a fiber optics type laryngoscope, the light source is mounted on the blade engaging end of the handle and the blade includes an optical fiber which registers with and carries light from the light source when the blade is mounted to the handle so that the laryngoscope functions as if the light source were mounted on the blade.
In the case of the conventional laryngoscope, the light source carried by its blade ultimately must be placed in electrical circuit with the batteries contained within its handle. This is accomplished by providing a passageway between the interior and exterior of the handle for accommodating an electrical contact between the batteries within the handle and the blade when the latter is mounted to the handle. In the case of the fiber optics type of laryngoscope, an additional passage is required to accommodate the light source which, as stated above, is carried by handle. There is still another type of prior art laryngoscope which is compatible with both conventional and fiber optic blades, as disclosed, for example, in the previously recited Upsher U.S. Pat. Nos. 4,406,280 and 4,517,964. This combination laryngoscope includes a handle having its own light source and two contacts, one for a conventional blade and the other for a fiber optics blade. When a fiber optic blade is mounted to this handle, it engages one of the contacts in order to energize the light source carried by the handle. When a conventional blade is mounted to the handle, it engages the other contact in order to energize its own light source without energizing the light source carried by the handle. Thus the handle of this combination laryngoscope requires not one or two but three passageways through its handle.
While laryngoscope of the type described above are generally satisfactory for their intended purpose, unless their handles are waterproofed, the handles cannot be cleaned by submerging them in water because the one or more passageways for accommodating the light source and/or electrical contacts serves as leakage paths to the batteries. One of the ways to solve this problem is to waterproof the passageways individually, as described in Bauman U.S. Pat. Nos. 4,669,449; 4,679,547; 4,694,822; 4,792,367; and 4,815,451. This approach requires as many as three individually sealed passageways for some laryngoscopes. This can be complicated, expensive and not always reliable.